Having an oversized air conditioner is an all too common problem, especially if your home is an older one. Before homes were built to the higher energy-efficiency standards that now exist, they required larger equipment because their cooling loads were higher. However, if you have improved your home’s airtightness and insulation over the years, you likely now have too large a cooling system.
The problems that oversized systems create include:
- Higher electric bills
- More frequent breakdowns
- Inadequate humidity removal
- Uneven cooling
Air conditioners that are too large start and stop more frequently, increasing the energy draw. When these systems first start, they use more electricity compared to what they use when they’re the right size.
It’s similar to your vehicle’s mileage. It goes up when driving on the highway, and falls in city traffic because of all the frequent stops and starts. And like your vehicle, it’s hard on the entire system to run in short cycles. All those starts increase stress, and the wear on parts hastens breakdowns.
The shorter running time doesn’t allow the evaporator coil inside the air handler to get cool enough to condense much of the water vapor in your home’s air. That extra humidity keeps you uncomfortable and can contribute to the increased risk of mold growth.
The humidity that does condense in an oversized air conditioner is more likely to evaporate back into the indoor air, since it doesn’t create a pool of water large enough to go down the drainpipe. Rooms that are farther from the air handler or facing south or west may not cool sufficiently, either, since the air doesn’t get properly distributed before the current cycle ends.
If you’re planning to replace your system in the near future, choose an HVAC contractor who will conduct a load calculation based on Manual J software. It takes into account your home’s size and layout, energy efficiency, and the amount of heat you generate indoors, among other factors.
To learn more about avoiding an oversized air conditioner, please contact us at Marsh Heating & Air Conditioning. We’ve provided trusted HVAC services for the Twin Cities area since 1974.
Our goal is to help educate our customers in Minneapolis-St. Paul, Minnesota about energy and home comfort issues (specific to HVAC systems). For more information about air conditioners and other HVAC topics, download our free Home Comfort Resource guide.
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